SUDDENLY IDLING LOW...

1992 Subaru SVX • 6 cylinder AWD Automatic • 126,384 miles

OK, stumbled across a 1992 Subaru SVX at a used car lot and after talking to the owner and a test drive, I fell in love. It has 126,000 miles on it, mint condition leather interior, etc. Everything seemed to be perfect, aside from needing new rear brakes. I just replaced the brakes 2 days ago, and now all of a sudden my car will start idling between 250 - 400 when warmed up and feels slightly shaky. At first, it started idling at around 600 - 800, which was odd to me because it seemed low to begin with. It seems like the idle is gradually dropping over time. The car still has impressive power and acceleration, but when tapping (not pressing) the accelerator when in park, the RPMs go up like normal, but as it drops down it will sputter and shake momentarily before going back to 300 - 400 RPMs. I'm not sure how long it's been since the fuel filter, plugs & wires, or anything has been done. Granted, it all needs to be done anyway, but I was wondering if I'm looking at something more severe, or what I should start looking at / replacing first. Originally, I thought vacuum leak or O2 sensor. Any ideas?

Should not be anything major. The idling speed is too low and and the most common causes for such problems are a dirty throttle body and Idle Air Control valve.

Get a can of carb cleaners, a piece of rag and a toothbrush. Remove the air intake hose. The throttle body should look gunky inside. Spray carb cleaner onto the gunks and open th throttle fully while using the rag to wipe off.

Use the tooth brush to get the remaining gunk off and remember to spray the cleaner into the ports inside the throttle body and allow to soak for a few minutes. Allow to dry out before starting as it is would be difficult to restart with too much carb cleaner inside.